Powder spray gun for spraying different color powders from a powder channel of a spray gun

ABSTRACT

A powder spray gun for spraying different color powders from a powder dispensing channel of the spray gun, with a connection mechanism possessing a number of connections at which there can be connected infeed conduits for different powder-conveying airmixtures and flushing air and through the agency of which there can be delivered to the spray gun-powder dispensing channel a selected powder-conveying air-mixture for spray coating thereof and flushing air for cleaning of such spray gun. The connection mechanism comprises a connection element carrying the connections, this connection element containing for each connection a continuous substantially straight connection channel. The connection element and the pistol body member containing the powder dispensing channel can be adjusted relative to one another in such a manner that the connection channels of the connection element can be connected by means of their outlet openings with the inlet opening of the powder dispensing channel in a certain sequence and with a given distribution of the infeed conduits for the powder-conveying air-mixture and the flushing air at the connections of the connection element the spray gun powder dispensing channel is flushed with flushing air during each color change.

United States Patent [191 Braun et al.

[111 3,782,632 11 Jan. 1,1974

Willi Huber, both of St. Gallen, all of Switzerland [73] Assignee: GemaAG Apparatebau, St. Gallen,

Switzerland 22 Filed: Aug. 1, 1972 211 Appl. No.: 277,082

Related US. Application Data [63] Continuation-impart of Ser. No.198,816, Nov, 15,

1971, abandoned.

[30] Foreign Application Priority Data Aug. 2, 1971 Switzerland 1.11345/71 Mar. 24, 1972 Switzerland 4417/72 [52] US. Cl. 239/112,239/305, 239/397, 222/1445 [51 Int. Cl. B051) 7/02 [58] Field of Search239/397, 394, 305, 239/390, 396, 450, 538, 540, 112; ZZZ/144.5;137/6254], 605

FORElGN PATENTS OR APPLICATIONS 56,982 10/1952 France ..239/396 770,33610/1934 France ..239/305 Primary Examiner-M. Henson Wood, Jr. AssistantExaminer-John J. Love Attorney-Karl W. Flocks- 57 ABSTRACT A powderspray gun for spraying different color powders from a powder dispensingchannel of the spray gun, with a connection mechanism possessing anumber of connections at which there can be connected infeed conduitsfor different powder-conveying airmixtures and flushing air and throughthe agency of which there can be delivered to the spray gun-powderdispensing channel a selected powder-conveying airmixture for spraycoating thereof and flushing air for cleaning of such spray gun. Theconnection mechanism comprises a connection element carrying theconnections, this connection element containing for each connection acontinuous substantially straight connection channel. The connectionelement and the pistol body member containing the powder dispensingchannel can be adjusted relative to one another in such a manner thatthe connection channels of the connection element can be connected bymeans of their outlet openings with the inlet opening of the powderdispensing channel in a certain sequence and with a given distributionof the infeed conduits for the powder-conveying air-mixture and, theflushing air at the connections of the connection element the spray gunpowder dispensing channel is flushed with flushing air during each colorchange.

6 Claims, 11 Drawing Figures PATENTEU 1 1974 SHEET 2 BF 5 FIG. 3

FIG. 5

9 QP QQQO POWDER SPRAY GUN FOR SPRAYING DIFFERENT COLOR POWDERS FROM APOWDER CHANNEL OF A SPRAY GUN This is a continuation-in-part ofcopending parent application Ser. No. 198,816 filed Nov. 15, 1971, nowabandoned.

BACKGROUND OF THE INVENTION The present invention relates to a new andimproved powder spray gun or pistol for spraying or coating differentcolor powders from a spray gun-powder dispensing channel andincorporating a connection mechanism possessing a number of connections,at which connection mechanism there can be connected infeed conduits fordifferent powder-conveying air-mixtures and flushing air and through theagency of which there can be delivered to the spray gun-powderdispensing channel a selected powder-conveying air-mixture for sprayingor coating purposes and flushing air for cleaning of such spray gun.

Now for the purpose of spraying different color liquid coating agents bymeans of a spray gun the prior art is acquainted with dye infeed deviceswhich can be mounted upon a spray gun. With the heretofore known coloror dye infeed devices a distributor provided with a continuous channelis generally arranged in a housing possessing inlet openings withconnections for connecting infeed conduits for the different colorcoating agents and also having a common outlet channel. The distributorallows for the selective connection of each inlet opening with theoutlet channel. In order to clean the distributor channel and the spraygun during each color change it was common practice to permit a newcolor to pass through the pistol for such time until the mixed colorshade disappeared. To that end means were provided at an infeedmechanism for the purpose of opening a needle valve of the spray gun forthe discharge of the color or dye when the atomization air was shut-off.Such infeed mechanisms are unsuitable for powder spray guns since thecolor powder tends to deposit at certain locations of the channel andthe deposited powder can again loosen at some time during spraying ofthe new color powder, so that after the color change operation there isno longer ensured for spraying of a clean true color.

SUMMARY OF THE INVENTION Hence, from what has been explained above itshould be apparent that this particular field of technology is still inneed of powder spray guns for spraying different color powders in amanner not associated with the aforementioned drawbacks and limitationsof the heretofore proposed constructions in the art. Thus, it is aprimary object of the present invention to provide an improvedconstruction of powder spray gun which effectively and reliably fullfilsthe existing need in the art and is not associated with theaforementioned drawbacks and limitations of the prior art proposalsconsidered above.

Another and more specific object of the present invention relates to anew and improved construction of powder spray gun having a color changeor switching mechanism by means of which as a practical matter theredoes not occur any color defects or flaws during switch-over from onecolor to another.

Yet a further significant object of the present invention relates to animproved spray gun for spraying dif' ferent color powders incorporatingmeans for effectively switching the spray gun for operation from onepowder color to another powder color without any deleteriousinterblending of the different powder colors.

Now in order to implement these and still further objects of theinvention, which will become more readily apparent as the descriptionproceeds, the connection mechanism embodies a connection elementcarrying the connections, this connection element is provided with acontinuous linear or straight channel for each connection. Theconnection element and a pistol body member containing a powderdispensing channel can be adjusted relative to one another in such amanner that the channels of the connection element can be connected bymeans of their outlet openings with the inlet opening of the powderdispensing channel in a certain sequence and for a correspondingdistribution of the infeed conduits for the powder-conveying airmixtureand the flushing air at the connections of the connection element thespray gun-powder dispensing channel is flushed with flushing air duringeach color change.

During a color change it is only necessary to adjust the infeed conduitconveying the new color and upon setting or adjustment of this infeedconduit the spray gun-powder dispensing channel is temporarily connectedwith the flushing air-infeed conduit and cleaned of the previouslysprayed powder, the pressure of the flushing air not being sufficient toatomize the powder in a manner appropriate for coating purposes, so thatthere is always only atomized a pure color powder. The connectionelement and the pistol body member can possess oppositely situated orconfronting surfaces into which open the connection channels and thepowder dispensing channel. At the the of th connection element there arearranged in a row the outlet opening of all connection channels with acenter point arranged along a line, the connection element and thepistol body member can be moved relative to one another along this linefor adjusting the outlet openings of the connection channel with respectto the inlet opening of the powder dispensing channel and with anappropriate shape of the pistol body member and whenever an outletopening is adjusted to the inlet: opening the surface of the pistol bodymember covers all of the remaining outlet openings. Such arrangement ofthe connection channels, wherein the outlet openings thereof arearranged in a row, renders possible a distribution of the infeedconduits feeding the powder-conveying airmixture and the flushing airwith respect to the connections of the connection element in such amanner that between each two infeed conduits conveying the pow der thereis arranged an infeed conduit conveying flushing air. As a result,during each color-change operation the powder dispensing channel of thepistol body member is automatically connected for flushing purposes withan infeed conduit for flushing air.

The confronting surfaces of the connection element and the pistol bodymember can be planar or flat and the outlet openings of the connectionchannels can be uniformly distributatively arranged along a circle or anare, so that the connection element can be designed as a circular diskor sector-shaped plate and rotatably mounted at an axis of rotation ofthe pistol body member. In order to be able to arrange a number of sprayguns above one another, something which is oftentimes desired, theconnection element is advantageously designed as a flat or planar slidewherein the outlet openings of the connection channels are located alonga straight line. The pistol body member can also be designed in the formof a rod having an axial powder channel, wherein the end of the powderchannel is outwardly curved, and wherein the inlet opening is located ata cylindrical jacket surface of the pistol body member at which there isrotatably mounted a connection element in the form of a hollow cylinder.The outlet openings of the connection channels are then located at aperiphery or a portion thereof in a uniformly distributed manner at theinner jacket surface of the connection element.

In order to prevent any line grinding or rubbing of the powder betweenthe pistol body member and the connection element and having such arriveas a defective color at the powder channel the inlet opening of thepowder channel is surrounded by a sealing ring which protrudes past thesurface of the pistol body member in order to only always seal-off theconnection channel which has been momentarily set at the outlet openingand to further maintain a small gap between the surfaces of theconnection element and the pistol body member through which leakage aircan escape from the flushing air-infeed conduits for continuous flushingpurposes. Such or similar type designs allow for a particularlyeconomical construction of the spray gun or pistol. Since, however, acolor powder-infeed conduit only can be connected at each secondconnection of the connection element there are required for the sprayingof different colors a number of small and easy to use or a number oflarge and therefore difficult to handle devices. According to apreferred embodiment of the invention a connection element constructedfor instance in the form of a truncated cone thus contains a centralconnection channel which can be connected at a flushing air-infeedconduit and a number of connection channels arranged about suchconnection channel which can be connected with the powder infeedconduits. The connection element is secured through the agency of aCardan suspension or mounting to the pistol body member in such a mannerthat it can be pivoted out ofa starting position in which the centralconnection channel is located at the inner opening of the powderdispensing channel at the pistol body selectively into positions inwhich a respective outer connection channel can be connected with thepowder dispensing channel. For adjusting the connection element therecan be provided suitable adjustment means such as pneumatic cylindermeans or lifting magnets wherein upon switching-in one of them it ispossible to pivot the connection element from the starting position intoan appropriate working position and upon switching-off the adjustmentmeans such connection element can be again placed back into its startingposition in which flushing of the spray gun occurs. The transfer andgrinding of the powder in this case is extremely negligible since thesurfaces which cover or overlap one another during the switchingoperation, and which come into contact with different powders, aresmall. The connection element is advantageously mounted by means of aCaradan joint at a casing or lining of the pistol body member. Thiscasing renders possible dispensing with a cover for the connectionchannels conveying the individual powders, since any possibly presentpowder can be sucked-out of the inner compartment.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be betterunderstood and objects other than those set forth above, will becomeapparent when consideration is given to the following detaileddescription thereof. Such description makes reference to the annexeddrawings wherein:

FIG. 1 is a schematic illustration of a spray installation containing apowder spray gun or pistol;

FIG. 2 is a longitudinal sectional view through an embodiment of powderspray gun for spraying different color powders and provided with aconnection mechanism for switching colors;

FIG. 3 is a fragmentary sectional view of the spray gun depicted in FIG.2, taken substantially along the line IIIIII thereof;

FIG. 4 is a schematic illustration of the connection element and gunillustrated in FIG. 2;

FIG. 5 is a schematic illustration of a sector-shaped connectionelement;

FIG. 6 is a schematic illustration ofa connection element which can bedisplaced relative to the spray gun;

FIG. 7 is a longitudinal sectional view of a further embodiment of spraygun and the therewith connected connection mechanism;

FIG. 8 is a longitudinal sectional view of still a further embodiment ofspray gun and therewith connected connection mechanism;

FIG. 9 is an end view of the arrangement depicted in FIG. 8;

FIG. 10 is a longitudinal sectional view of a powder spray gun withcolor switching mechanism of a further exemplary embodiment; and

FIG. 11 is an end view of the connection element as viewed along theline XIXI of FIG. 10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing now thedrawings, and turning attention initially to the exemplary illustratedembodiment of apparatus depicted in FIG. 1 serving for the powdercoating of articles or the like, such will be seen to incorporate, forinstance, six powder containers 1 containing six different colorpowders. At the lower end of each such funnel-shaped powder container 1there is arranged a respective associated injector 2. Conveying air isdelivered to each injector 2 by means of a'respective associatedconveying line or conduit 4 provided with a respective suitable shut-offvalve 3. An infeed conduit and line 5 leads from each injector 2 to acommon connection mechanism 7. Additionally, there is also connectedwith this connection mechanism 7 a flushing air conduit or line 6.

A gun or pistol 8 of conventional design is directly mounted in operableassociation at the connection mechanism 7. Connection mechanism 7 can beadjusted into different positions, so that when assuming a first givenposition one of the powder infeed conduits 5 is placed in flowcommunication with the spray gun 8 and there is carried out a coatingoperation by means of the relevant color powder received from one of theassociated containers 1. All of the other powder infeed conduits 5 andalso the flushing air conduit 6 are sealed in this first position withrespect to the spray gun 8, that is to say, do not flow communicate withthe spray gun 8 in this first position of the connecting mechanism 7.During a color-change operation the connecting mechanism 7 is first ofall adjusted so as to assume a position such that the flushingair-infeed conduit 6 is now connected with the spray gun 8.Consequently, spray gun 8 is flushed by clean air through the agency ofthe connection mechanism 7. Thereafter, this connection mechanism 7 canbe adjusted into a position where coating with a different color canoccur.

With the embodiment of spray gun 8 and connection mechanism 7 asdepicted in the embodiment of FIGS. 2 and 3 there is provided a coverplate 10 at the stationary gun body member 9, of which only a portionhas been shown. A bearing pin or journal 11 is fixedly seated at coverplate 10, and a substantially diskshaped connection element or portion12 is rotatably mounted at such bearing pin 11. This closure element 12possesses eight connections 13 constructed in the form of studs 13a forthe connection of a like number of conduit hoses, such as theschematically illustrated conduit hose 50 of FIG. 2. Each connection 13is provided with a continuous connection channel 18. The outlet ordischarge openings 19 of these channels 18 are all located at an endsurface or face of the connection element 12.

As best seen by referring to FIG. 4 a respective powder infeed conduitAe and a flushing air-infeed conduit Sp are alternately connected withthe connections 13. Upon rotating the connection element 12 the powderinfeed conduits Ae and the flushing air-infeed conduits Sp arealternately brought into flow communication with the spray gun-powderdispensing channel 14.

When one of the powder infeed conduits Ae is placed into flowcommunication with the spray gun-powder dispensing channel 14 then it ispossible to carry out a coating operation with a certain desired powdercolor. Upon rotating the connection element 12 and during a color-changeoperation always one of the flushing airinfeed conduits Sp moves pastthe spray gun-powder dispensing channel 14, so that the spray gun isalways cleaned before beginning coating with a different powder color.

At the gun end surface or face 16 there is provided a sealing ring'l5about the inlet opening 17 of the powder dispensing channel 14, and bymeans of which sealing ring 15 there is obtained good sealing of themomentarily set connection channel 18. The outlet openings 19 of theremaining connection channels 18 are covered by the closure plate 10,whereby however no sealing ring is provided between such cover plate 10and the connection element 12, so that there is prevented escape ofcolor powder from the corresponding connection channels, whereas leakageair departing from the flushing air-infeed conduits Ae continuouslyflushes the gap between the components 10 and 12 and thus also bringsabout a certain rearward displacement of the color powder out of theassociated connection channels. What has been discussed above is alsoanalogously applicable for the embodiments of the invention to bedescribed hereinafter. The cover plate 10 for the disk-shaped form ofthe connection element 12 depicted in FIGS. 2 and 4 is of the same sizeas the connection element 12, so that the space requirements for thisarrangement are small. The flexible hoses 50 (only one of which has beenshown in FIG. 2) connected with the connection element 12 permitrotation of such element.

FIG. 5 illustrates a substantially sector-shaped connection element 12which is rotatably mounted about a bearing pin 11 and wherein theconnections 13 and structed in the form of a slide, wherein the outletopenings 19 of the connection channels 18 are located in a linear row,and at the connections there are alternately connected powder infeedconduits Ae and flushing air delivery conduits Sp. The mode of operationin this case is the. same as the previously described embodiments,wherein only, however, the connection element 12 must be linearlydisplaced instead of rotated. The cover plate 10 at the pistol bodymember must be twice as long as the connection element 12, so thatduring its displacement all connections are covered. With thisembodiment the hoses are not rotated and there is possible a so-calledsandwich construction for a coating installation having a number ofpowder spray guns, wherein the guns are grouped together into anassembly or unit.

With the embodiment depicted in FIG. 7 the connection element 12 isarranged so as to be stationary and possesses connections 13 at whichthere can be alternately connected powder infeed conduits Ae andflushing air-delivery conduis Sp. The spray gun body member 9 isarranged in such a way that it resiliently presses against thestationary connection element 12 and thus brings about by means of blindplugs or stoppers 21 a good sealing of all of the connection channels18. The gun body member 9 is detachable from the connection element 12and can be rotated in its lifted-off position and the powder dispensingchannel 14 extends arcuately from the outside towards the center fromthe region of the inlet opening 17 and such inlet opening duringrotation of the gun body member 9 is alternately brought into connectionor flow communication with the different connection channels 18. Owingto rotation of the gun body member 9 there is brought about acolor-change operation, wherein during each changeover operation thereoccurs a cleaning of the spray gun with flushing air. In this case thehoses are not rotated. However a sandwich construction :is not herepossible.

With the embodiment of FIGS. 8 and 9 a hollow, cylindrical stationaryconnection element 12 possesses connections 13 designed in the form ofinclined connection studs, and at which connections 13 there can bealternately connected powder infeed conduits Ae and flushingair-delivery conduits Sp. The cylindrical spray gun body member 9 isrotatably mounted at the connection element 12. The gun body member 9possesses an arcuate channel portion 22 extending from the periphery upto the center and is provided at its periphery at the region of theconnection element 12 with two sealing rings 23. By rotating the gunbody member 9 the powder dispensing channel 14 can alternately be placedinto flow communication with one of the powder delivery conduits inorder to be able to work with a desired color. During a color-changeoperation the channel inlet opening 17 always moves past anintermediately situated flushing air conduit and therefore is cleaned.By virtue of the sealing rings 23 there is formed an air cushion betweenthe gun body member 9 and the connection element 12, preventing anyrubbing or grinding of powder and thus binding of the gun body member 9.This arrangement requires very little space, the hoses are not rotated,and finally a sandwich construction is possible.

With the embodiment illustrated in FIGS. 10 and U the gun body member 9is provided at the region of the inlet opening 17 of the powderdispensing channel 14 with a mouthpiece 24 and is mounted at a casing orlining 25. In this casing 25 there is mounted through the agency of aCardan connection or joint 26 a connection element 12A in such a mannerthat it can pivot to all sides about its center. The connection elementHA is provided with a central connection channel 18A at which there canbe connected a stud-like connection 13 for a flushing air-deliveryconduit. In the illustrated starting position of the connection element12A the flushing air-delivery conduit is in flow communication via theconnection channel 18A with the spray gunpowder dispensing channel 14.Six further connection channels 188 are formed at the connection element12A about such central connection channel 18A, the respective centerline of these connection channels 188, as apparent from the drawings,being located upon the surface of a truncated cone. Each of theseconnection channels 188 extends through a stud-like connection 13 atwhich there can be connected a powder delivery conduit for the deliveryof a color powderconveying air-mixture. The connection element 12A isprovided at the discharge side of the connection channels 18A, 188 witha segmented spherical-shaped sealing surface 27, the center of which islocated at the point of rotation of the Cardan joint arrangement 26.This sealing surface 27 is bounded by an upstanding edge 28 which at theoutside of the outer connection channels 188 extends in arcuate-shapedfashion and in a wedge-like manner between such connection channels, asbest seen by referring to FlG. 11. Owing to the cooperative action ofthe edge 28 with the mouthpiece 24 the deflection or pivotal movement ofthe connection element 12A is limited in such a manner that in eachpivoted position one of the outer connections 18B is in flowcommunication with the spray gun-powder dispensing channel 14. Thedeflection or pivoting of the connection element 12A occurs through theagency of pneumatic cylinders 36 which act upon a flange 29 of theconnection element 12A and wherein a respective one of such pneumaticcylinders is associated with each outer connection channel 1188. Uponactuating one of the cylinders 30 the connection element 12A is pivotedin such a manner that the associated outer connection channel 188 isconnected in flow communication with the powder dispensing channel 14.After switching-off the cylinder 30 connection element 12A returns backinto its starting position under the action of any suitable andtherefore not particularly illustrated return or restoring forceproducing means, such as a spring for instance, in which the flushingoperation occurs and from which, upon actuating an appropriate cylinder,such can be again moved into a different deflected position.

Of course instead of using the pneumatic cylinders 30 there can beemployed other actuating means, such as lifting magnets, for deflectingthe connection element 12A. Moreover, instead of having a cylinder 30which is axially directed and which cooperates with the flange 29 therecould also be employed radially directed cylinders 30 for the deflectionof the connection element 12A, as such has been illustrated in phantomlines in FIG. 10.

While there is shown and described present preferred embodiments of theinvention, it is to be distinctly understood that the invention is notlimited thereto but may be otherwise variously embodied and practicedwithin the scope of the following claims. ACCORD- INGLY,

What is claimed is:

l. A powder spray gun arrangement for spraying different color powderscomprising a spray gun including a spray gun body member having a powderdispensing channel for spraying different color powders, a connectionmechanism having a number of connections, infeed conduits for differentpowder-conveying airmixtures and flushing air connectable with saidconnection mechanism and through the agency of which there can bedelivered through the spray gunpowder dispensing channel for sprayingpurposes a given selected powder-conveying air-mixture and for cleaningof the spray gun flushing air, said connection mechanism comprising aconnection element carrying said connections, said connection elementbeing provided with a respective substantially continuous straightconnection channel for each connection, each said connection channelhaving an outlet opening and said powder dispensing channel having aninlet opening, means for mounting said connection element and said spraygun body member having said powder channel so as to be displaceablerelative to one another such that said connection channels of theconnection element can be selectively connected by means of their outletopenings with the inlet opening of the powder channel in a certainsequence, and with a predetermined distribution of the feed conduits forthe powder-conveying air-mixture and the flushing air at the connectionsof the element the powder dispensing channel is flushed with flushingair during each color-changeover operation, said connection element andsaid gun body member possessing oppositely situated surfaces at whichrespectively open said connection channels and said powder channel, saidoutlet openings of all said connection channels being arranged in a rowat the surface of said connection element with a center point locatedalong a line, said connection element and said gun body member beingable to be moved relative to one another along said line for adjustingsaid outlet openings with respect to said inlet opening of said powderchannel, and wherein when any one of said outlet openings is adjustedwith respect to said inlet opening so as to be in flow communicationtherewith said gun body member covers by means of its surface saidoutlet openings of all the remaining connection channels, said inletopening of said powder dispensing channel being surrounded by a sealingring by means of which that connection channel which is located in anoperable position can be sealed at the region of its outlet opening,said connection element and said gun body member being arranged suchthat a gap is present between said connection element and said gun bodymember, leakage air entering from said connection channels into said gapand said gap being continuously flushed by such leakage air.

2. A powder spray gun arrangement for spraying different color powderscomprising a spray gun including a spray gun body member having a powderdispensing channel for spraying different color powders, a connectionmechanism having a number of connections, infeed conduits for differentpowder-conveying airmixtures and flushing air connectable with saidconnection mechanism and through the agency of which there can bedelivered through the spray gunpowder dispensing channel for sprayingpurposes a given selected powder-conveying air-mixture and for cleaningof the spray gun flushing air, said connection mechanism comprising aconnection element carrying said connections, said connection elementbeing provided with a respective substantially continuous straightconnection channel for each connection, each said connection channelhaving an outlet opening and said powder dispensing channel having aninlet opening, means for mounting said connection element and said spraygun body member having said powder channel so as to be displaceablerelative to one another such that said connection channels of theconnection element can be selectively connected by means of their outletopenings with the inlet opening of the powder channel in a certainsequence, and with a predetermined distribution of the infeed conduitsfor the powder-conveying air-mixture and the flushing air at theconnections of the element the powder dispensing channel is flushed withflushing air during each color-changeover operation, one of saidconnection channels of said connection element defining a centralconnection channel which can be connected to a flushing air infeedconduit, the remaining connection channels being connectable with saidpowder infeed conduits and arranged about said central connectionchannel, Cardan-suspension means for suspending the connection elementat the gun body member in such a manner that it can be selectivelypivoted out of a starting position in, which said central connectionchannel is connected with said powder dispensing channel intopredetermined positions wherein a given respective outer connectionchannel is connected with the powder channel.

3. The powder spray gun arrangement as defined in claim 2, wherein saidgun body member possesses a casing, said Cardan-suspension :meansembodying a Cardan joint arrangement for mounting the connection elementat the casing of the gun body member.

4. The powder spray gun arrangement as defined in claim 2, wherein theouter connection channels are arranged at the connection element aboutthe central connection channel in such a manner that each respectivecenter line thereof is located at a surface of a truncated cone.

5. The powder spray gun arrangement as defined in claim 3, wherein saidgun body member is provided with a mouthpiece, said connection elementpossessing at the outlet side of the connection channels a substantiallysegmented spherical-shaped sealing surface against which bears saidmouthpiece of the gun body member, and wherein the center of saidsealing surface is located at the point of rotation of the Cardan jointarrangement.

6. The powder spray gun arrangement as defined in claim 5, wherein saidsealing surface is arranged about the outlet openings of the outerconnection channels and is bounded by raised edge portions which in cooperation with the mouthpiece of the gun body member limit the pivotalmovement of the connection element.

1. A powder spray gun arrangement for spraying different color powderscomprising a spray gun including a spray gun body member having a powderdispensing channel for spraying different color powders, a connectionmechanism having a number of connections, infeed conduits for differentpowder-conveying air-mixtures and flushing air connectable with saidconnection mechanism and through the agency of which there can bedelivered through the spray gunpowder dispensing channel for sprayingpurposes a given selected powder-conveying air-mixture and for cleaningof the spray gun flushing air, said connection mechanism comprising aconnection element carrying said connections, said connection elementbeing provided with a respective substantially continuous straightconnection channel for each connection, each said connection channelhaving an outlet opening and said powder dispensing channel having aninlet opening, means for mounting said connection element and said spraygun body member having said powder channel so as to be displaceablerelative to one another such that said connection channels of theconnection element can be selectively connected by means of their outletopenings with the inlet opening of the powder channel in a certainsequence, and with a predetermined distribution of the feed conduits forthe powder-conveying air-mixture and the flushing air at the connectionsof the element the powder dispEnsing channel is flushed with flushingair during each color-changeover operation, said connection element andsaid gun body member possessing oppositely situated surfaces at whichrespectively open said connection channels and said powder channel, saidoutlet openings of all said connection channels being arranged in a rowat the surface of said connection element with a center point locatedalong a line, said connection element and said gun body member beingable to be moved relative to one another along said line for adjustingsaid outlet openings with respect to said inlet opening of said powderchannel, and wherein when any one of said outlet openings is adjustedwith respect to said inlet opening so as to be in flow communicationtherewith said gun body member covers by means of its surface saidoutlet openings of all the remaining connection channels, said inletopening of said powder dispensing channel being surrounded by a sealingring by means of which that connection channel which is located in anoperable position can be sealed at the region of its outlet opening,said connection element and said gun body member being arranged suchthat a gap is present between said connection element and said gun bodymember, leakage air entering from said connection channels into said gapand said gap being continuously flushed by such leakage air.
 2. A powderspray gun arrangement for spraying different color powders comprising aspray gun including a spray gun body member having a powder dispensingchannel for spraying different color powders, a connection mechanismhaving a number of connections, infeed conduits for differentpowder-conveying air-mixtures and flushing air connectable with saidconnection mechanism and through the agency of which there can bedelivered through the spray gunpowder dispensing channel for sprayingpurposes a given selected powder-conveying air-mixture and for cleaningof the spray gun flushing air, said connection mechanism comprising aconnection element carrying said connections, said connection elementbeing provided with a respective substantially continuous straightconnection channel for each connection, each said connection channelhaving an outlet opening and said powder dispensing channel having aninlet opening, means for mounting said connection element and said spraygun body member having said powder channel so as to be displaceablerelative to one another such that said connection channels of theconnection element can be selectively connected by means of their outletopenings with the inlet opening of the powder channel in a certainsequence, and with a predetermined distribution of the infeed conduitsfor the powder-conveying air-mixture and the flushing air at theconnections of the element the powder dispensing channel is flushed withflushing air during each color-changeover operation, one of saidconnection channels of said connection element defining a centralconnection channel which can be connected to a flushing air infeedconduit, the remaining connection channels being connectable with saidpowder infeed conduits and arranged about said central connectionchannel, Cardan-suspension means for suspending the connection elementat the gun body member in such a manner that it can be selectivelypivoted out of a starting position in which said central connectionchannel is connected with said powder dispensing channel intopredetermined positions wherein a given respective outer connectionchannel is connected with the powder channel.
 3. The powder spray gunarrangement as defined in claim 2, wherein said gun body memberpossesses a casing, said Cardan-suspension means embodying a Cardanjoint arrangement for mounting the connection element at the casing ofthe gun body member.
 4. The powder spray gun arrangement as defined inclaim 2, wherein the outer connection channels are arranged at theconnection element about the central connection channel in such a mannerthat each respective center line thereOf is located at a surface of atruncated cone.
 5. The powder spray gun arrangement as defined in claim3, wherein said gun body member is provided with a mouthpiece, saidconnection element possessing at the outlet side of the connectionchannels a substantially segmented spherical-shaped sealing surfaceagainst which bears said mouthpiece of the gun body member, and whereinthe center of said sealing surface is located at the point of rotationof the Cardan joint arrangement.
 6. The powder spray gun arrangement asdefined in claim 5, wherein said sealing surface is arranged about theoutlet openings of the outer connection channels and is bounded byraised edge portions which in cooperation with the mouthpiece of the gunbody member limit the pivotal movement of the connection element.